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Move updating of the window size to the monitor process.

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This will allow us to close the slave in the main sudo process in
the future so only the command and monitor have it open.
This commit is contained in:
Todd C. Miller
2018-08-20 10:04:14 -06:00
parent db8a760b0f
commit 6953e7fc79
4 changed files with 187 additions and 111 deletions
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63
src/exec_monitor.c
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@@ -1,5 +1,5 @@
/*
* Copyright (c) 2009-2017 Todd C. Miller <Todd.Miller@sudo.ws>
* Copyright (c) 2009-2018 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@@ -17,6 +17,7 @@
#include <config.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <stdio.h>
@@ -32,6 +33,7 @@
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <termios.h>
#include "sudo.h"
#include "sudo_event.h"
@@ -58,6 +60,8 @@ struct monitor_closure {
struct sudo_event *sigchld_event;
};
static bool tty_initialized;
/*
* Deliver a signal to the running command.
* The signal was either forwarded to us by the parent sudo process
@@ -97,6 +101,11 @@ deliver_signal(struct monitor_closure *mc, int signo, bool from_parent)
"%s: unable to set foreground pgrp to %d (command)",
__func__, (int)mc->cmnd_pgrp);
}
/* Lazily initialize the pty if needed. */
if (!tty_initialized) {
if (sudo_term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]))
tty_initialized = true;
}
killpg(mc->cmnd_pid, SIGCONT);
break;
case SIGCONT_BG:
@@ -119,6 +128,34 @@ deliver_signal(struct monitor_closure *mc, int signo, bool from_parent)
debug_return;
}
/*
* Unpack rows and cols from a CMD_TTYWINCH value, set the new window
* size on the pty slave and inform the command of the change.
*/
static void
handle_winch(struct monitor_closure *mc, unsigned int wsize_packed)
{
struct winsize wsize, owsize;
debug_decl(handle_winch, SUDO_DEBUG_EXEC);
/* Rows and colums are stored as two shorts packed into a single int. */
wsize.ws_row = wsize_packed & 0xffff;
wsize.ws_col = (wsize_packed >> 16) & 0xffff;
if (ioctl(io_fds[SFD_SLAVE], TIOCGWINSZ, &owsize) == 0 &&
(wsize.ws_row != owsize.ws_row || wsize.ws_col != owsize.ws_col)) {
sudo_debug_printf(SUDO_DEBUG_INFO,
"window size change %dx%d -> %dx%d",
owsize.ws_col, owsize.ws_row, wsize.ws_col, wsize.ws_row);
(void)ioctl(io_fds[SFD_SLAVE], TIOCSWINSZ, &wsize);
deliver_signal(mc, SIGWINCH, true);
}
debug_return;
}
/*
* Send status to parent over socketpair.
* Return value is the same as send(2).
@@ -210,7 +247,7 @@ mon_handle_sigchld(struct monitor_closure *mc)
send_status(mc->backchannel, mc->cstat);
}
}
} else {
} else {
sudo_debug_printf(SUDO_DEBUG_WARN,
"%s: not overwriting command status %d,%d with %d,%d",
__func__, mc->cstat->type, mc->cstat->val, CMD_WSTATUS, status);
@@ -328,10 +365,16 @@ mon_backchannel_cb(int fd, int what, void *v)
mc->cstat->val = n ? EIO : ECONNRESET;
sudo_ev_loopbreak(mc->evbase);
} else {
if (cstmp.type == CMD_SIGNO) {
switch (cstmp.type) {
case CMD_TTYWINCH:
handle_winch(mc, cstmp.val);
break;
case CMD_SIGNO:
deliver_signal(mc, cstmp.val, true);
} else {
break;
default:
sudo_warnx(U_("unexpected reply type on backchannel: %d"), cstmp.type);
break;
}
}
debug_return;
@@ -414,7 +457,7 @@ fill_exec_closure_monitor(struct monitor_closure *mc,
/* Setup event base and events. */
mc->evbase = sudo_ev_base_alloc();
if (mc->evbase == NULL)
sudo_fatal(NULL);
sudo_fatal(NULL);
/* Event for command status via errfd. */
mc->errpipe_event = sudo_ev_alloc(errfd,
@@ -513,11 +556,9 @@ exec_monitor(struct command_details *details, sigset_t *oset,
int errpipe[2];
debug_decl(exec_monitor, SUDO_DEBUG_EXEC);
/* Close unused fds. */
/* The pty master is not used by the monitor. */
if (io_fds[SFD_MASTER] != -1)
close(io_fds[SFD_MASTER]);
if (io_fds[SFD_USERTTY] != -1)
close(io_fds[SFD_USERTTY]);
/* Ignore any SIGTTIN or SIGTTOU we receive (shouldn't be possible). */
memset(&sa, 0, sizeof(sa));
@@ -529,6 +570,10 @@ exec_monitor(struct command_details *details, sigset_t *oset,
if (sudo_sigaction(SIGTTOU, &sa, NULL) != 0)
sudo_warn(U_("unable to set handler for signal %d"), SIGTTOU);
/* If we are starting in the foreground, the pty was already initialized. */
if (foreground)
tty_initialized = true;
/*
* Start a new session with the parent as the session leader
* and the slave pty as the controlling terminal.
@@ -559,6 +604,8 @@ exec_monitor(struct command_details *details, sigset_t *oset,
sigprocmask(SIG_SETMASK, oset, NULL);
close(backchannel);
close(errpipe[0]);
if (io_fds[SFD_USERTTY] != -1)
close(io_fds[SFD_USERTTY]);
restore_signals();
/* setup tty and exec command */